Low-Complexity Sphere Decoding Detector for Generalized Spatial Modulation Systems

This letter presents a sphere decoding strategy for generalized spatial modulation (GSM) systems. The proposed modifications reduce the exhaustive tree search for lattice points and exploits the structure of GSM, restraining the tree branches to those that result in valid antenna combinations. As a result, every found lattice point results in valid GSM transmitted symbols. The numerical results exhibit significant complexity reduction.